Hydatid disease is a significant public health problem in certain areas of western United States: however, the epidemiology and methods of transmission of this disease are poorly understood by the majority of inhabitants which live in this region. Our project is directed towards an identification of factors which contribute to the spread and distribution of this disease, improved diagnostic techniques for the detection of the parasite in vertebrate hosts, and the development of suitable educational aids for individuals who live in communities where the disease is endemic. Studies proposed for the coming year include: (1) continued surveillance of Echinococcus granulosus in sheep and dogs in two endemic foci identified thus far, (2) completion of educational aids for Navajo Indians, (3) development of suitable sero-diagnostic tests for hydatid cysts in intermediate hosts, (4) analysis of an attitudinal survey now completed for inhabitants of a community where hydatid disease is endemic, (5) comparison of growth patterns, response to chemotherapeutic agents, and response to sero-diagnostic tests for E. granulosus, E. multiocularis, and Taenia hydatigena, and (6) investigation of the potential of domestic cats serving as definitive hosts for Echonococcus spp. in this region.